In silver halide color photographic materials, as photographic couplers that will react with the oxidized product of an aromatic primary amine developing agent to form color-formed dyes, generally a yellow coupler, a magenta coupler, and a cyan coupler are used in combination.
The color-formed dyes obtained from these couplers are required to have, for example, excellent spectral absorption properties and high fastness to light, heat, humidity, etc. The excellent spectral absorption properties desired in photographic materials should be such that color-formed dyes formed from respective couplers do not have undesired absorption in wavelength regions other than the desired major absorption. For example, in the case of yellow color-formed dyes, since the major absorption part of the formed and is broad, the color reproduction of yellow hue and green hue is unsatisfactory.
In color print materials to be used for recording and storing images, conventionally, pivaloylacetanilide-type yellow couplers are used. However, since the major absorption of the yellow dyes obtained from these couplers is broad, the color reproduction is unsatisfactory and a technique for its improvement is desired. The fastness of the color-formed dyes obtained from the above-mentioned yellow couplers is poorer than that of the color-formed dyes obtained from magenta couplers and cyan couplers, the change in color balance of the respective color-formed dyes during long-term storage is conspicuous, and therefore the improvement is strongly desired.
Thus, to improve light-fastness of such yellow color-formed dyes, steric hindrance phenol compounds described, for example, in JP-A ("JP-A" means unexamined published Japanese patent application) Nos. 48535/1979 and 222853/1985, polyalkylpiperidine compounds described, for example, in JP-B ("JP-B" means examined Japanese patent publication) No. 20617/1982 and JP-A Nos. 116747/1984 and 11935/1984, and compounds described, for example, in JP-A Nos. 239149/1987, 240965/1987, 254149/1987, and 300748/1990, are known, and when yellow couplers are used in combination with these compounds, fastness to light is indeed improved. However, the improved effect is still not at the satisfactory level, and it is found that, for example, the stability of the emulsion is deteriorated.
The deterioration of the stability of the emulsion results in serious problems in photographic performance; that is, (1) after a lapse of time the coupler dissolved in the oil droplets deposits, thereby causing coating trouble or a drop in the color density, or (2) after a lapse of time the diameter of the oil droplets increases, thereby causing a decrease called haze and lowering of the apparent color density.
Thus, no technique that can satisfy all of the above performances has yet been developed.